WASHINGTON — North Korean leader Kim Jong Un described his summit last month with President Donald Trump as “the start of a meaningful journey” and predicted in a letter made public Thursday that it would lead to a “new future” between the two countries.

“I deeply appreciate the energetic and extraordinary efforts made by Your Excellency Mr. President for the improvement of relations between the two countries and the faithful implementation of the joint statement,” an English translation of the letter that Trump posted on Twitter read.

The letter, which was dated July 6, drew attention on social media for repeatedly describing Trump as “your excellency,” a title often reserved for royalty. It was unclear whether the phrase was simply a formality used by Kim or whether there was something lost in translation.

The term has frequently been used by foreign leaders to refer to presidents. In a 2009 press conference, then Chinese President Hu Jintao began his opening remarks by calling President Obama “your excellency.”

Fatmir Sejdiu, the former president of Kosovo, used the phrase in a letter to Obama congratulating him on winning the Nobel Peace Prize in 2009.

Trump posted the Korean and English versions of the letter on Twitter, describing it as a “a very nice note from Chairman Kim of North Korea.” He added that “great progress being made!”

Shortly after that summit, Trump declared that the nuclear threat from North Korea was over, but critics have questioned whether North Korea will in fact give up its nuclear program — a central demand for Trump.